Isn't that only because they offer unpaywalled versions to web crawlers in the first place, so they still get ranked in search results?

I would want to see a search engine which will not index paywalled articles and will not execute JavaScripts and CSS (so that any part of the document that requires JavaScripts to be displayed will not be indexed, and search queries involving such parts of the documents will not find those documents; documents that require JavaScripts to be displayed at all will not be indexed at all).